WO1994000628A1

WO1994000628A1 - Method of maintaining pressure of continuous heat-treating machine for synthetic fiber tow

Info

Publication number: WO1994000628A1
Application number: PCT/JP1993/000834
Authority: WO
Inventors: Takahisa Kida
Original assignee: Japan Exlan Company Limited
Priority date: 1992-06-24
Filing date: 1993-06-22
Publication date: 1994-01-06
Also published as: DE4392925T1; GB2274854B; JP3173669B2; EP0617151A4; US5433914A; GB2274854A; JPH0610229A; GB9400988D0; DE4392925C2; TW226037B; EP0617151A1; EP0617151B1

Abstract

In a continuous heat-treating machine for synthetic fiber tows, this invention provides a method of maintaining a pressure which causes less leakage of a heat medium vapor and provides high stability in maintaining the pressure of a pressure chamber. An aspect ratio of an outlet seal portion of the pressure chamber is set to be smaller than that of an inlet seal portion of the pressure chamber. The method of the invention causes smaller damage to the fiber to be heat-treated, provides a small unit requirement of a heat medium vapor, and is excellent in operation stability and uniformity of heat-treatment.

Description

Specification

Method of maintaining pressure in continuous heat treatment machine for synthetic fiber

The present invention relates to a method for maintaining pressure in a pressure chamber of a continuous heat treatment machine for synthetic fiber tow.

Background art

Heat-treating the synthetic fiber to which the temporary crimp has been applied by the crimping device through a heat treatment machine having a pressure chamber filled with steam or the like is a process of the synthetic fiber manufacturing process. It has been heavily used as one. One

The synthetic fiber tow (hereinafter also abbreviated as a crimped fiber mass) is charged into the pressure chamber in a straight or stretched shape, and then pulled from the pressure chamber. Several methods have been proposed to maintain the pressure in the pressure chamber during pumping.

One method is to fill the pressure seal section, which is provided before (inlet) and after (outlet), the pressure chamber, with a crimped fiber mass. That is what it is. Usually, in such a heat treatment machine, a crimped fiber mass is transferred between a pair of upper and lower endless conveyor belts. In this pressure sealing method, the fiber mass is transferred to the inside of the pressure seal portion. This is only possible if there is frictional resistance between the endless conveyor belt and the pressure inside the pressure chamber that exceeds the pressure in the pressure chamber.

Therefore, in order to increase the frictional resistance and prevent the leakage of a heat medium such as water vapor in the pressure chamber, it is necessary to increase the apparent density of the crimped fiber mass when charging the pressure chamber. I did. When crimped fiber masses with a high apparent density are introduced into the pressure chamber, the fiber packing density on the endless conveyor belt is large and the heat treatment plant The time required is long and the equipment becomes long. In addition, as the heat treatment proceeds in the pressure chamber, the crimped fiber mass undergoes heat shrinkage, and the cross-sectional area of the crimped fiber mass when passing through the pressure seal at the pressure chamber outlet side becomes smaller. .

As a result, the frictional resistance between the fibrous mass and the endless belt will decrease due to the decrease in the normal force, and can therefore be secured up to that point. The balance with the internal pressure was lost, and the crimped fiber mass was blown off to the outside of the outlet-side pressure seal part, making it difficult to maintain a stable pressure in the pressure chamber. It was customary. In order to improve these drawbacks, the crimped fiber mass may be stretched when it is charged into the pressure chamber, but the time required for heat treatment in this case is reduced. It can be completed in a shorter time as long as the fiber packing density on the endless comparison belt is lower than when it is not stretched-but the fiber to be processed at the pressure seal at the pressure chamber outlet side The problems such as the problem of blow-out to the outside and damage to the fiber to be treated have not been solved.

In the end, the method of filling both the inlet and outlet pressure seals with crimped fiber mass is not widely adopted, and the outlet side pressure seal is replaced with a labyrinth seal. I'll be there. However, the fiber is frequently damaged by direct rubbing between the labyrinth part and the high-temperature heat-treated fiber, and the fiber can only pass through the crimped and stretched fiber. However, this method is not entirely satisfactory in terms of problems such as the need for a long labyrinth seal at high pressure.

The second pressure maintaining method, which is further improved as described above, includes crimping by arranging a nozzle at the inlet and / or outlet pressure seals. Seal while holding down fiber mass There is a so-called roller seal system. However, at the outlet side, high pressure is applied to the crimped fiber mass that has reached a high temperature, so that multiple single yarns may be fused or damaged. In addition, a cooling chamber is provided at the outlet side and in front of the lasil part to cool the crimped fiber mass once Improvements have been made to seal, but not only do the equipment become more complicated and longer, but also the quality of the fiber to be treated ^ is completely satisfactory. It was not.

Thus, no method has yet been found that can prevent the equipment from being lengthened, has excellent stability in maintaining the pressure in the pressure chamber, and satisfies the quality such as damage to the fiber to be heat-treated.

An object of the present invention is to overcome the above-mentioned current problems in a continuous heat treatment machine, to have excellent stability in maintaining the pressure in a pressure chamber without deteriorating the quality of a fiber to be heat-treated, and An object of the present invention is to provide a pressure maintaining method capable of handling a large number of brands.

Summary of the Invention

The above-mentioned object of the present invention is to sandwich a crimped synthetic fiber tow between endless conveyor belts of 1 mm above and below to form a pressure chamber filled with a heat medium vapor at or above atmospheric pressure. During continuous heat treatment, the tow discharged from the crimping device is charged into a pressure chamber, and then the heat-treated synthetic fiber drop is drawn out from the pressure chamber. The length and width of the outlet of the pressure chamber is made smaller than the width and width of the seal at the inlet of the pressure chamber. It is preferably achieved.

—In addition, in the present invention, the vertical dimension of the pressure chamber outlet seal is reduced by the clearance between a pair of upper and lower endless conveyor belts. The only way to reduce the lateral dimension is to use a pair of left and right endless belts that run at least through the pressure chamber outlet seal on both sides of the 卜. This is done by narrowing the competition belt inward.

According to such a method, the vertical and horizontal dimensions of the rectangular cylindrical seal portion on the pressure chamber outlet side on which the heat-shrinked crimped fiber mass travels are smaller than the vertical and horizontal dimensions of the section on the pressure chamber inlet side. Thus, the frictional resistance between the heat-treated crimped fiber mass and the upper and lower and left and right endless conveyor belts and the endless belt again develops, excellent pressure maintenance is achieved, and the heat-treated fiber mass is reduced. There is no trouble to blow out to the outside, and it is possible to deal with brands with different sizes of crimped fiber mass at the outlet.

Hereinafter, the present invention will be described in detail.

The continuous heat treatment machine for synthetic fiber tow according to the present invention (hereinafter, simply referred to as a heat treatment machine, and the treatment by the machine is referred to as heat treatment) is a vertical type in which the tow travels vertically. Including horizontal type or horizontal type that runs horizontally, general horizontal type is explained.In the center, there is a pressure chamber filled with heat medium vapor above atmospheric pressure. In addition, a pressure seal portion that seals the pressure in the pressure chamber by filling the fiber to be heat-treated before and after, that is, on the inlet and outlet sides, is provided. Fiber inlet pressure Seal part-pressure chamber-outlet pressure The movement of the seal part is of the type that is conveyed between endless conveyor belts that are provided in one pair at the top and bottom.

The synthetic fiber tow is charged into the heat treatment machine by a crimping device provided immediately before the inlet side pressure seal portion. In the present invention, the synthetic fiber tow provisionally crimped by the crimping device is formed into a lump as a crimped fiber mass as described above, and the discharging force of the crimping device is used. It is charged in the inlet pressure seal. The reason why the term "assumes" here is that, as described later, the crimp given here may be appropriately stretched.

The crimped synthetic fiber drop is easy to obtain a high apparent density without damaging itself, has a large friction resistance pile in the pressure seal section, and has good pressure sealability. It is recommended that the crimp here be 8 pitch Zinch to l2 pitch Zinch. This means that the crimping device inlet tow speed is about 10 times the speed of the crimped fiber mass exiting the crimping device.

In the case of synthetic fiber tow to which no temporary crimp has been applied, a drawing device (for example, a multi-stage roller) is separately required in the pressure chamber, and a sufficient seal is provided by the pressure seal section. In order to exhibit its properties, it is necessary to pass through a very narrow pressure seal part, and damage to the fiber itself is unavoidable, etc. The difference from the method is lost and the invention cannot be achieved.

The dimensions of the pressure seal section on the inlet side of the pressure chamber should match the vertical and horizontal dimensions of the crimped fiber mass formed by the crimping device. In the present invention, a pair of upper and lower endless pairing bells is used in the vertical direction. This is done by adjusting the clearance between the birds. In the lateral dimension, if the sandwiching from the top and bottom is sufficient, the crimped fiber mass will expand in the lateral direction, so that sufficient frictional resistance can be obtained even with a fixed width. .

Of course, the left and right sides are set to run on both sides of the toe. A pair of endless belts may be run not only at the outlet-side pressure seal portion but also at the inlet-side pressure seal portion, and the width of the compare belt may be shifted inward to control the lateral dimension.

Thus, the crimped fiber mass that has passed through the inlet side seal portion is sandwiched or wrapped by the pair of upper and lower endless belts or the pair of left and right endless belts and the pressure chamber. Is transported.

At this time, the discharge speed of the crimped fiber mass discharged from the crimping device

(A m / min) and the traveling speed (transport speed B m / m Γη) of the above-described comparator need not necessarily be the same, and may be であれば ≥ Α.

The case where B> A— is the state with elongation. B is divided by A and the value is defined as the elongation ratio. This stretching ratio can be easily set and controlled only by adjusting the discharge speed of the crimping device and the above-mentioned conveyor belt traveling speed. In the actual operation, whether the crimp is fixed (seed) by heat treatment, whether the required residence time of the heat treatment machine is secured, or whether the crimp is completely extended When this is done, the draw ratio is set in consideration of factors such as a reduction in frictional resistance at the outlet-side pressure seal part, and the like, but generally 1 to 4 are often used.

Thus, by the above-mentioned conveyor belt, a crimped fiber mass which is sandwiched between the upper and lower sides or wrapped around the upper, lower, left and right sides and conveyed in the pressure chamber while being appropriately stretched. When heated by the heat medium vapor, the temperature rises, and in most synthetic fibers, the fiber shrinks in the fiber axis direction, the apparent density of the crimped fiber mass increases, and the volume decreases. That is, the length and width of the crimped fiber mass It is smaller than the room entrance.

In the conventional case where the vertical and horizontal dimensions of the pressure seal are the same as the inlet and outlet sides, in this state, heat medium vapor and fibers to be heat-treated are blown out from this state via the outlet pressure seal. This pressure maintenance cannot perform the necessary heat treatment.

The present invention is characterized in that the length and width of the pressure seal portion on the outlet side of the pressure chamber on the outlet side through which the crimped fiber mass having a reduced volume, that is, the length and width are reduced, is made smaller than that on the inlet side. As a result, frictional resistance is generated between the crimped fiber mass having a reduced volume and the pressure seal portion in the upper, lower, left and right directions, and pressure sealing can be performed.

Outlet pressure In order to reduce the vertical and horizontal dimensions of the seal part, the above-mentioned inlet pressure is used in addition to the installation of a pressure seal part that has been made small in size from the beginning. As described in the seal section, the vertical dimension is to reduce the clearance between a pair of upper and lower endless belts, and the horizontal dimension is a pair of left and right endless belts. Is performed by shifting the width inward. As described above, if one of the lengthwise or widthwise direction of the heat-treated crimped fiber mass is sandwiched, the other becomes larger, so the lengthwise or widthwise dimension is reduced in either the lengthwise or widthwise direction. It may be one or the other.

The pair of upper and lower endless belts are made of heat- and abrasion-resistant material with good heat-vapor vapor permeability, and penetrate through the heat treatment machine from the entrance to the exit □. The same characteristics are required for a pair of left and right endless belts, but the running range is limited to the inlet-side pressure seal and the outlet-side pressure seal, or even the outlet-side pressure seal. Good. In addition, it is not always necessary to provide a drive train for traveling. For example, an endless vertical competition A pair of left and right endless belts may be sandwiched between both ends of the belt, and a width-regulated passage may be provided at the outlet side or at the outlet side and inlet side pressure seals through which they pass.

Outlet pressure The vertical and horizontal dimensions of the seal should be compared to the vertical and horizontal dimensions of the inlet side, depending on the type of material to be heat-treated and the total denier slewing and crimping pitch. It cannot be specified unconditionally because it varies depending on factors such as the number of cables, the elongation rate to be set, the contraction rate of the material, and the vapor pressure of the heat medium applied to the pressure chamber. As a function of the vapor pressure of the heat medium, which has the greatest influence, the reduction ratio of the vertical and horizontal dimensions (reduction rate of the exit dimensions to the entrance dimensions%), which is a guideline, is as follows. is there

Immediate Chi, 1 kg / cm ² G vertical 1 0-1 8% than Ri side, lateral 1-3% level, 2 kg / cm ² respectively in G s 1 8-2 2%, 3-7%, 3 In kg / cm ² G, it is 22 to 25% and 7 to 12%.

In the method described in detail above, even if the length and width of the crimped fiber mass to be heat-treated are changed by the heat treatment, the length and width of the outlet-side pressure seal portion are made narrower than the inlet portion. However, the gap between the crimped fiber mass and the leakage of the heat medium vapor is reduced. In addition, in order to fill the crimped fiber mass into the pressure seal part, compared to the roller seal method in which the crimped fiber mass is squeezed with ¾ pressure while leaving a space in the left-right direction. Even if the pressing force applied to the fiber is very low, the pressure sealing effect can be obtained. For the same reason, a long labyrinth seal facility on the exit side is not required. In addition, a pair of left and right endless belts are interposed between the heat-treated crimped fiber mass and the fixed centering member, especially at the outlet-side pressure seal section. Left and right of fiber mass No rubbing action on both end surfaces.

Example

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a continuous heat treatment machine showing one embodiment of the method of the present invention. A synthetic fiber tube 1 to be heat-treated is supplied from the left side of the figure and formed into a crimped fiber mass 3 by a crimping device 2. The pressure chamber inlet seal portion 4, pressure chamber 5, and pressure chamber outlet are provided. This shows a state in which the crimped fiber mass 3 is conveyed to the right with a pair of upper and lower endless conveyor belts 貫通 running on a stone penetrating through the inside of the seal portion 6.

FIG. 2 is a cross-sectional view of the pressure chamber inlet seal portion 4 of FIG. 1 taken along a plane perpendicular to the traveling direction of the crimped fiber mass 3. It is shown that there is a pair of endless comparison belts 7 above and below the crimped fiber mass 3 in the inlet seal part.

FIG. 3 is a cross-sectional view of the pressure chamber-outlet seal 鄧 1, which is perpendicular to the direction of travel of the crimped fiber mass 3. A pair of endless belts 7 on the upper and lower sides of the crimped ingot 3 and a pair of endless belts 9 on the left and right sides are fixed inside the outlet seal part. This indicates that there is a narrowing member 8 that has been set.

FIG. 4 is a cross-sectional view showing an outlet seal portion 6 according to another embodiment of the present invention. In the outlet part, a vertical adjustment member 10 and a pair of upper and lower endless comparison belts 7 are mounted vertically, and a pair of left and right endless belts 9 are mounted on the left and right sides and fixed outside. This shows that the width-shifting member 8 is present.

Example 1—

Referring to the drawings, FIG. 1 is a longitudinal sectional view of a continuous heat treatment machine for carrying out the present invention, and shows a synthetic fiber tow 1 (in this embodiment). Is a acryl-based 88,000 tol tar denier ゥ) is supplied from the left side of the figure, and is formed by a crimping device 2 into a crimped fiber mass 3 having a traveling speed of 12 m / min. It was transported to the right by being sandwiched between a pair of upper and lower endless comparison belts 7 running 18 m min to the right in the figure, and was set to 18 mm long and 200 mm wide. The liquid was conveyed to the pressure chamber 5 through the pressure chamber inlet seal portion 4 having a rectangular cross section and having a cylindrical shape. The elongation rate is 1.5.

Fig. 2 is a cross-sectional view of the entrance seal portion 4 taken along a plane perpendicular to the traveling direction of the crimped fiber mass 3, and a pair of left and right sandwiching the left and right of the crimped fiber mass 3 as shown in the figure. There is no endless belt. There were no gaps visible to the naked eye at the top, bottom, left and right inside the rectangle of the crimped fiber mass 3 and the inlet seal 4.

The pressure chamber outlet seal portion 6 is a tubular member having a rectangular cross section having the same vertical and horizontal dimensions as the inlet seal portion. However, the width adjustment member 8 for narrowing the lateral dimension is fixed, and the pair of right and left endless belts (rubber) 9 are run. The actual lateral dimension of the outlet seal is 190 mm (see FIG. 3).

The pressure chamber 5 has a structure in which saturated steam is introduced as heating medium vapor from above and below the chamber, and condensed water is discharged from the lower bottom of the chamber. Are not shown.) Eleven

In this embodiment, steam at a gauge pressure of 2.0 kg / cm ² was introduced, but during the heat treatment, the fluctuation of the pressure gauge provided in the pressure chamber was only ± 0.06 kgcm ² . In fact, almost no leakage of water vapor was noticeable to the naked eye from the inlet seal part originally from the outlet seal part. one The flow rate of the integrated condensed water flow meter discharged from the lower bottom of the pressure chamber was 96.4% by weight with respect to the flow rate of the integrated steam flow meter provided in the middle of the steam introduction pipe to the pressure chamber 5. I did. This value is not perfect because it is affected by the moisture carried in the heat-treated crimped fiber mass, but it is a measure of the amount of water vapor leaking from the pressure seal, and high sealing performance is obtained. It indicates that there is.

The state of the pressure chamber outlet seal portion 6 is shown in FIG. 3 as a cross-sectional view of a plane perpendicular to the traveling direction, similarly to FIG. According to Fig. 3, the heat-treated crimped fiber mass 3 is sandwiched between a pair of upper and lower endless conveyor belts 7 on the upper and lower sides, and a pair of left and right non-bells are shifted to the left and right in the same manner. It will be understood that it is sandwiched between boxes 9. At the end of this experiment, all driving of the moving object was stopped at once, and the outlet seal was dismantled to confirm that the crimped fiber mass 3 and the outlet seal 6 had a rectangular interior. There were no visible gaps on the left and right.

The crimped fiber mass to be heat-treated in this example was subjected to predetermined post-treatment, and then the physical properties of the fiber were evaluated. The evaluation items were the dyeing degree range (difference between the maximum and minimum values of the degree of dyeing), which represents the variance in the width and length directions of the toe of the dyeing degree, and 200 filaments after heat treatment. The percentage of single fibers having a crack longer than the length of the fiber by microscopic observation of the fiber (the degree of damage expressed as% I, and the left and right end faces of the crimped fiber mass after heat treatment) Observation by microscopic observation of 200 single fibers collected from the sample alone showed excessive abrasion, which was expressed as the percentage (%) of single fibers that had been cut or abraded.

In both the first and second evaluation items, the value is small if the pressure sealing property of the outlet pressure sealing part is good. This is the pressure -If the heat-treated fiber mass is exposed to a widely fluctuating pressure or blows out, the uniformity of the heat treatment is lost and the dyed color becomes uneven. Similarly, if a high-temperature fiber is hit against a device wall or the like with a strong impact force, cracks and tears, such as cracks and tears, occur in the single fiber. The third excessive friction means that the fibers on the left and right walls at the outlet side pressure seal portion are literally rubbed, and the smaller the friction, the better.

The evaluation results showed that the degree of dyeing was 0.58%, the degree of damage was 2.0%, and the degree of rubbing was 1.1%, indicating that the method was an excellent method of maintaining pressure. It is understood that high-quality heat-treated fibers are obtained, including the left and right ends of the mass.

Comparative Example 1

The same as in Example 1 except that the lower endless conveyor belt was left for conveying the crimped fiber mass and the inlet seal and the outlet seal were replaced with roller seal devices. In the heat treatment machine, the heat treatment of Example 1 was performed by a roller seal method. For that to prevent leakage of water vapor and out port side port one la chromatography sealing device or, et al., The inlet side 3 kg Bruno cm ² G was Tsu Der but Russia over la first seal device of the outlet side 5 kg Roh cm The pressure gauge fluctuation in the pressure chamber, which required a roller surface pressure of ² G, was ± 0.04 kg / cm ^{2. The} condensate flow rate ratio was 97.0% by weight, and the Maintainability and leakage of water vapor were not a problem.

The dyeing degree range was also good at 0.50%, but the damage degree reached 30%, indicating that the outlet roller seal was severely damaged. Excessive friction refers to the left and right end faces of the crimped fiber mass to be evaluated. Since there was no part to be evaluated, it could not be evaluated.

Comparative Example 2

In the heat treatment machine of Example 1, the heat treatment was performed under the same conditions as in Example 1 except that the width-adjusting member 8 of the pressure chamber outlet seal portion 6 and the pair of left and right endless belts 9 were removed. I did it. There was intermittent discharge of crimped fiber mass with water vapor from the outlet seal, and satisfactory operation was not possible, but a small amount of sample was obtained. One

The results of this experiment were the fluctuation of the pressure gauge ± 0.5 kg Zcm ² , the condensate flow rate 63.5 wt%, the degree of dyeing degree 2.58%, the damage degree 25%, and the excessive friction 8. It was 0%. It can be understood that the heat treatment was uneven, the leakage of water vapor was severe, and the fibers were also undergoing major damage, in conjunction with the visual observation. In addition, even in the case of the experimental sample that was collected occasionally, since the abrasion damage was large, the effect of preventing the abrasion damage of the pair of left and right endless belts was remarkable as compared with Example 1. You can see that.

Example 2

In the heat treatment machine of Example 1, the pressure chamber outlet seal portion has the same shape as that of Example 1 and has a length of 14 mm and a width of 200 mm, and has a width adjusting member 8. The heat treatment was carried out under the same conditions as in Example 1 except that the pair of left and right endless belts running inside the exit seal was also removed. Good operation has been achieved and enough samples have been humiliated. Leakage of water vapor was not observed at the entrance seal, but was slightly observed at the exit seal.

The results of this experiment were as follows: fluctuation of pressure gauge ± 0.08 kg / cm ² , condensate flow ratio 93.7% by weight, dyeing degree range 0.66%, loss With a flaw of 4.0% and abrasion of 4.3%, it can be seen that a stable pressure maintenance with little water and steam leakage was achieved, and a uniform heat treatment with little damage was performed. However, since there was no pair of left and right endless belts, abrasion damage occurred somewhat in comparison with Example 1.

Example 3

In the heat treatment machine of Example 1, the upper and lower adjustment members 10 were provided at the top and bottom of the pressure chamber outlet seal to reduce the clearance between the pair of upper and lower endless comparison belts. The heat treatment was carried out under the same conditions as in Example 1 except that the pressure chamber outlet seal was perpendicular to the crimped fiber lump advancing direction (see FIG. 4). Extremely stable operability was obtained, and no leakage of water vapor to the naked eye was observed at both the inlet and outlet seals.

The results of this experiment were as follows: fluctuation of pressure gauge ± 0.3 kg / cm ² , condensate flow ratio 97.7 wt%. Dyeing degree range 0.43%, damage degree 0.5%, excessive friction It is evaluated to be 0.6%, and is particularly excellent in both pressure maintenance and heat-treated fiber quality.

As described above, the method of the present invention can stably maintain the heat treatment vapor pressure without causing significant damage such as cracks, abrasions, and cuts to the heat-treated fibers. It is a method that is highly stable in operation, for example, has little unevenness in heat treatment, for example, non-uniform dyeing, and many brands in which the dimensions of crimped fiber mass after heat treatment change. Being able to process is also a derived effect. In addition, heat medium vapor leakage is low, that is, heat medium vapor basic unit is excellent.One of the methods is energy saving method, and heat medium vapor does not leak to the workplace. Therefore, there are many industrial significances such as a sanitary working environment.

Claims

Range of request

1. To continuously heat the crimped synthetic fiber tow through a pressure chamber filled with heat medium vapor at atmospheric pressure or higher, sandwiched between a pair of upper and lower endless conveyor belts. At this time, when the tow discharged from the crimping device is charged into the pressure chamber, and then the heat-treated synthetic fiber towel is drawn out of the pressure chamber, the length and width α of the pressure chamber outlet seal portion are reduced.

A method for maintaining the pressure of a continuous heat treatment machine for synthetic fiber る, characterized in that the dimensions are made smaller than the vertical and horizontal dimensions of the pressure chamber inlet seal.

2. A pair of left and right endless belts that run on both sides of the toe are provided at least at the pressure chamber outlet seal, and the endless belts are widened inward. The method for maintaining pressure of a continuous heat treatment machine for synthetic fiber tubes according to claim 1.

3. The method according to claim 1, wherein the clearance between the pair of upper and lower endless conveyor belts is reduced at the pressure chamber outlet seal. A method for maintaining the pressure of a continuous heat treatment machine for synthetic fibers.